Next to our neighbours Leyandii hedge we find that hellebors do particularly well. We also grow a couple of Smoke Bushes (proper name?) to give a contrasting colour to the hedge along with a golden conifer.

Did you mean Cotinus, Bulba?

I do indeed, thank you. We have a pale green one and a dark red one, both of which stand out well against the dark of the hedge. Another plant growing well there is Astrantia major.